In 1644 the news that Antonio de Montezinos claimed to have discovered the Lost Tribes of Israel in the jungles of South America spread across Europe and the Ottoman Empire fuelling an already febrile atmosphere of eschatological and millenarian expectation, culminating in the claims of Sabbatai Sevi to be the Jewish messiah. By tracing the process in which one set of apocalyptic ideas was transmitted across the Christian and Islamic worlds, this book provides fresh insight into the origin and transmission of eschatological constructs, and the resulting beliefs that blurred traditional religious boundaries and identities.Divided into four case studies this book demonstrates that the great events of the early modern period - the expulsions and conversions in Iberia, the Reformation, the development of professional diplomacy, the expansion of long-distance trade, and the advent of the news industry - led to the creation of transnational networks along which apocalyptic constructs could be widely disseminated. Beginning with an investigation of the impact of de Montezinos's publications, the next chapter follows the story to England, examining the how the Quaker messiah James Nayler was viewed in Europe and the Ottoman empire. The third chapter presents the history of the widely reported - but wholly fictitious - story of the sack of Mecca, a rumour that was spread alongside news of Sabbatai Sevi. The final chapter looks at Christian responses to the Sabbatian movement, providing a detailed discussion of the cross-religious and international representations of the messiah. The conclusion brings these case studies together, arguing that the evolving beliefs in the messiah and the Lost Tribes between 1648 and 1666 can only be properly understood by taking into account the multitude of narrative threads that moved between networks of Jews, Conversos, Catholics, Protestants from one side of the Atlantic to the far side of the Mediterranean and back again. By situating this transmission in a broader historical context stretching back to 1492, the book reveals the importance of early-modern crises, diasporas and newsgathering networks in generating the eschatological constructs, disseminating them on an international scale, and transforming them through this process of intercultural dissemination into complex new hybrid religious conceptions, expectations, and identities.